Ars Technica is running an interesting article about the Mail application on Windows 8. It's one of the first party Metro applications, and Ars' conclusion is that it's really, really not up to snuff - it can't even compare favourably to the mail application on Windows Phone. The sad thing is, however - this applies to virtually all Metro applications.

.Net was around for a good ten years. win 32 has been around since 1995 and still works up to win 7. That's actually pretty good support.

In theory you are right, Win32 still works up to Windows 7.

However, due to numerous bugs in the implementation which got fixed over the years, many applications that were originally written for Windows 95 - even if they use the proper Win32 APIs - won't work on a modern Windows 7 anymore since they relied on bugs in the Win32 API.

Just ask the wine developers, they know Win32 by heart. A friend of mine is actually an official wine developer and he has told me dozens of stories about bugs in Win32 which make it impossible to re-implement Win32 by just adhering the documentation.

Same with DirectX. Ever wondered why Steam reinstalls DirectX for almost every game you install? Isn't the idea of a library that it can be shared with all applications using it without having to reinstall? Well, Microsoft is constantly fixing DirectX over and over again that most games will only run properly if run with the DirectX version they were linked against.

I'd love to see Longbow 2 running on winXP or win7 remotely stable. I'd be pleased as punch just to watch the load up and intro even if it then crashes out of the main menu. It was written for windows; why it no run on Windows?

However, due to numerous bugs in the implementation which got fixed over the years, many applications that were originally written for Windows 95 - even if they use the proper Win32 APIs - won't work on a modern Windows 7 anymore

They work much better than some Nextstep app from those times if you try to run them on present OSX. OSX apps from a short decade ago, also have huge issues - and you can't even escape into "oh but you can install those obsoleted libs" ( http://www.osnews.com/thread?526828 plus, Java Cocoa and Carbon were full citizens, and were retired) ...something which, yeah, you can do almost anywhere - but it's really funny how here, with DX, you suddenly make a 180 turn, and treat shipping libs with apps as a defect.

I even have one nice win16 app (a dictionary) in use...

PS. WRT to all-in-one ( http://www.osnews.com/permalink?526829 ) - well, I hear smartphones are all the rage, and super-all-in-one is what they're really about.
Overall, we won't really know how well it can work, in the areas targeted by Metro, unless somebody seriously tries (and remember that Windows only became good and took over from 3.x onwards)